Stadia attachment for angle-indicators.



R. L. MQOORMICK.

STADIA ATTACHMENT FOR ANGLE INDICATORS.

APPLICATION I'ILBD JAN. 5, 1912.

1,048,718. Patented Dec.31,1912.

544m mtoz V ma M Zd.

a HOT/"$13 scope 9 of UNITED STATES PATENT OFFICE.

RO ERT L. McCORMICK, '01 mm HAUTE, 'INDIANA.

STADIA arr'aonmnur'pron ANGLE-INDVIGAIIQRS.

' Application filed January Specification of Letters Patent.

Patented Dec. 31, 1912.

5, 1912. Serial No. 669,571.

. To all whom; it may concern:

Be it known that 1, ROBERT L. MCCOR- MICK, a citizen of the United States, residing at Terre Haute, in the county of Vigo and State of Indiana, have invented a new and useful Stadia Attachment for Angle.

of my invention is to produce point may. be mechanically determined as a result of a proper setting of the transit relative to such, point, and by means of which the horizontal distance between the transit station and such point-may be also mechanically indicated. More broadly stated, my invention comprises three cooperating members for the mechanical indication of the stadi'a diagram values 2 sin. 21)

cos. 2?)

where Rzstadia rod reading and ozthe angle of inclination of a transit reading.

The accompanying drawings illustrate my invention.

Figure 1 is a front elevation of the attachment, Fig. 2 a side elevation; and Fig. 3 a diagram. In the,, drawings, 10 indicates a head which may be clamped upon astud projecting axially from the trunnion of the telethe transit. This head 10' carries an arm 11 in a plane at right anglesto the pivotal axis of the telescope, and pivotally connected to the outer end of this arm, at 12, is alink 13, the length of which is equal to the length of arm 11 between the axis of head 10 and the pivot 12. The outer end of link 13 is pivotally connected at 14 to a slide 15 which is freely slidable in a fixed head 16 along a right line which is at right.

angles to the axis of head 10 and in a plane parallel with the" plane, of swing of the telescope.

Link 13 carries a scale 17 which is arbit-rarily divided into main divisions, each conveniently indicating one hundred feet,

and subdivided into 10 foot divisions. Slidably mounted upon the scale 17 is a head 18 having a Vernier scale 19 designed to cooperate with the scale 17, the head 18 being capable of relationship with the scale 17.

I Slidably mounted in a guide 21, which is mounted upon arm 11 and is parallel with the plane of swing of the telescope, is a scale 22 divided into major divisions which of scale 17 but'are marked to indicate the same readingas the major divisions of scale 17; i. 6., for example, 100 feet. The major divisions of scale 22 may be subdivided as Mounted upon guide 21 is a stationary vernier 23 arranged to cooperate with scale 22. "Scale 22 may be shifted in its guide Way 21 by any suitable means, such, for instance, as the rack 24 and pinion 25.

Mounted upon one end of scale 22, above scale 17, is a transverse head 26 which is in a plane parallel with the plane of swing of optical axis of vthe telescope at all times. Head 26 is provided with a vernier' 27 which cooperates with a scale 28 which is slidably v mounted in the head'26 and may be-clamped major divisions of the'scale 28 are equal to those of the scale 22. Pivotally mounted upon the vernier'head 18 is a second -ver- 'nier .31, the pivot 32 of which is parallel with the horizontal axis of thetelescope and this pivoted Vernier 31 is arranged to cooperate with scale 28.

when the telescope has its optical axis in the horizontal plane, the zero of've'rnier 18 may be brought to the zero of scale 17 the zero of scale.22- may be brought to the zero of'vernier 23, and the zeros of verniers 27 and 31 will-be in alinement with each other .and with any reading of scale 28 depending upon the position which said scale 28 occupies With relation to head 26. Inthis position of the parts, the pivot points 12 and 14 will be in. alinement with each other and with a point on the axis of head 10.

In operation, with the transit placed above any station-of known elevation, say 500 feet, scale 28 will be set with its mark indicating are twice the length of the major divisions desired, conveniently intoi5 foot divisions.'

the telescope and is also parallel with the in any position by clamping screw 29. The

The several scales aresoarranged that,I

being brought into any desired reading and is there clamped in place.

Scale 22 is then shifted to bring scale '28 intoengagement with Vernier 31, said vernier swinglng upon its pivot to come into cooperation with the adjacent edge of scale 28; The position upon scale 28 indicated by the zero of Vernier 31; will be a closely .20 approximate designation of the vertical elevation of the point upon which the stadia rod is resting, referred to the same datum as the transit station. The reading .on scale 22, as indicated by. vernier 23, when added to half the stadia rod reading will be equal (within-a generally negligible error) to the horizontal distance of the rod point f th transit station.-

when the arm 11 and link 13 are in 80 alinement and with the zero of head 18 in registry with the zero of scale 17, the zero of the swinging vernier 31 lies in the axis of the pivotal connection 12- then the above readings mentionedv as indicating the 35 horizontal and vertical position of the rod station will not be absolutely accurate, missing accuracy only by the constant 0f the transit, but, as this constant issmall and .wlll be a readily computable quantity, and alsoa 40 readily ascertainable quantity from existing tables prepared for each transit, the slight departure from exact accuracy is ordinarily ignored even by present methods ofcomputation. If greater accuracy is desired in '45 order to take account of the constantof the instrument, as indicated by the more complete formulae E sin. 21) f sin '2) and cos. 2v) +f cos. c;

the desired result may be accomplished by so arranging the zero of scale 17 that, when the zero of scale 19 of head 18 is in registry, therewith, the zero of the swinging Vernier 31 will lie above the axis of the 0 pivotal point 12 a distance equal to f' where f is the constant of the transit reduced to the scale of scale 17; and by so arrangingthe zero of scale 22 that, when scale 28 is brought down against the swinging Vernier 653l and the zero of' scale 19 is inregistrytherefore the formula may for all l iractical purposes be Written with the zero of scale 17, it will lie above the zero of the fixed scale 23 an amount J equal to Mathematically this conclusion is reached as follows: The complete formulae being it maybe writteii gsin. 2 0 sin 2'0 andv still be as accurate as desired because, the values of o and f are both very small and forall-practical purposes sin. 212:2 sin. 5 c,'at least as close as the scales can" be practically read. Consequently for all practical purposes, a

and if the zero of Vernier 31 'is set f distance above the center of ivot;12 when the zero of scale 19 is coincident with the zero of scale 17, then the distance. indicated as in Fig. 3 will be I ad was,

and 160 sin. 22;

- Similarly, for the very small angles v which are used, cos, a -cos; 2o practically and R f 5 cos. 2c+ co Zv and gmay beincluded inthe readings by setting the zero of scale 22 a distance above the zero of scale 23. O

, he mathematical demonstration of the instrument is as follows Arm 11 being equal in length ,to link, 13, the angle '0 of 125 inclination of arm 11 from the normal line L' of coincidence of arm 11 and link 13, due to the corresponding displacement angle of i the telescope from ,horizontal, will be equal to one-half of the supplemental angle be- '13,;

tween arm 11 and link 13; i. 6., angle 21), Fig. 3. The divisions of scale 17' being onehalf the size of those of scale 28, and scale 28 being graduated to indicate the elevation of the transit station, and R indicating any stadia rod reading, distances on scale 17 (the division of which are one-half the absolute size of those on the other two scales) will correspond to g for comparison with distances on the other scales. Using a distance, determined by the setting of the vernier 19, on scale 17 as the hypotenuse of a right angle triangle whose base is the medial line of arm 11, the other sideX of the triangle will be equal, or rather will correspond to and the distance determined by the reading upon scale 22, which will indicate that portion of arm 11 which will be the base of the triangle, will correspond to sin. 2'0,

R oos. 212.

%(1 cos. 21)) which equals R R cos. 2v.

equals the reading on scale 22, the horizontal distance between the transit station and cos. 2a

the stadia rod station will be, .of course, half the rod reading added to the reading on scale 22.

Scale 17 might be graduated in major divisions having the same magnitude as the major divisions of the other two scales but in that case the stadia rod reading would have to be divided by two in order to determine the proper setting of head 18.

I claim as my invention:

1. A stadia attachment for angle indicators comprising an arm for attachments to and to swing with the angle indicator, a link pivotally connected to said arm at one end and having its other end supported to slide along a line passing through the axis of the arm and indicator, said link having a length equal to the length of the arm be- I tween its axis and its pivotal connection with the link, a graduated scale carried by the link, an indicator head cooperating with and movable along said scale, a second indicator carried by said indicator head and pivoted thereon on an axis parallel with the axis of the arm, a second graduated scale coiiperating with said second indicator and arranged to be shiftable in a plane parallel with the plane of angle' indication of the angle indicator, a support for said second scale carried by the arm and movable lengthwise thereof, and a third graduated scale affording longitudinal readings for variation of position of the second scale lengthwise of the arm, the primary divisions of the first scale being one-half the size of corresponding divisions of the second and third scales. 7

2. A stadia attachment for angle indicators comprising an arm for attachment to and toswing with the angle indicator, a link pivotally connected to said ,arm at one end and having. its other end supported to slide along a line passing through the axis of the arm and indicator, said link having a length equal to the length of the arm between its axis and its pivotal connection with the link, a graduated scale carried by the link, an indicator head coiiperating with and movable along said scale, a second indicator carried by said indicator head, a second graduated scale cotiperating with said second indicator and arranged to be shiftable in a plane parallel with the plane of angle indication of the angle indicator, a-

slide along a line passing through the axis of the arm and indicator, a graduated scale carried by the' link, an indicator head cooperating with and movable along said scale, a second indicator carried by said indicator head and plvoted thereon onan axis parallel with the axis of the arm, a second graduated scale coiiperating with said second indicator and arranged to be shiftable for said second scale carried by the arm and movable lengthwise thereof, and a third in a plane parallel with the plane of angle indication of the angle indicator, a support graduated scale'aifording longitudinal readings for variation of position of the second scale lengthwise of the arm," the primary divisions'of the first scale being one-half the size of corresponding divisions of the second and third scales.

4. A stadia attachment for angle .indicators comprising an arm for attachment to and to swing with the angle indicator, a link pivotally connected to said arm at one end and having its other end supported to slide along a line passing through'the axis of the arm and indicator, a graduated scale carried by the link, an indicator head coiipcrat-ing with and movable along said scale, a second. indicator carried by said indicator head, a second graduated scale cooperating with said second indicator and arranged to be shiftable in a plane parallel with the plane of angle indication of the angle indicator, a support for said second scale carried by the arm and movable lengthwise thereof, and a third guaduate'd scale affording longitudinal readings for variation of position of the second scale lengthwise of the arm, the primary divisions of the first scale being one-half the size of corresponding divisions of the second and third scales.

5. A stadia attachment for angle indicators comprising an arm for attachment to and to swing with the angle indicator, a link pivotally connected to said arm at one end and having its other end supported to slide along a line passing through the axis of the arm and indicator, said link having a length equal to the length of the arm between its axis and its pivotal connection with the link, a graduated scale carried by the link, an in dicator head cotiperating with and movable along said scale, a second indicator carried by said indicator head and pivoted thereon on an axis parallel with the axis of the arm, a second graduated scale coiiperating with said second indicator and arranged to be shittable in a plane parallel with the plane of angle indication of the angle indicator, a support for said second scale carriedby the arm and movable lengthwise thereof, and athird graduated; scale afi'ording longitudinal readings for variation of position of the second scale lengthwise of the arm.

-6. A stadia attachment for angle indicators comprising an arm for attachment to and to swing with the angle indicator, a link pivotally connected to said arm at one end and having its other end supported to slide along a line passing through the axis of the arm; and indicator, said link having a length equal to the length of the arm between .its axis and its pivotal connection with the link,a graduated scale carried by the link, an indicator head 'coiiperating with and movable along said scale, a second indicator carried by said indicator head, a second graduated scale cooperating with said second indicator and arranged to be shiftable in a plane parallel with the plane of angle indication of the angle indicator, a support for said second scale carried by the arm and movable lengthwise thereof, and a third graduated scale afiording longitudinal readings for variation of position of'the second scale lengthwise of the arm.

7. A stadia attachment for angle indicators comprising an arm for attachment to and to swing with the angle indicator, a link pivotally connected to said arm at one end and having its other end supported to slide along a line passing through the axis of the arm and indicator, a graduated scale carried by the link, an indicator head cooperating with and movable along said scale, a second indicator carried by said indicator head and pivoted thereon on an axis parallel with the axis of the arm, a second graduated scale cooperating with'said second indicator and arranged to be shiftable in a plane parallel with the plane of angle indication of the angle indicator, a support for said second scale carried by the arm and movable lengthwise thereof, and a third graduated scale affording longitudinal readings for variation of position of the second scale lengthwise of the arm.

8. A stadia attaclnnent for angle indicators comprising an arm for attachment to and to swing with the angle indicator, a link pivotally connected to said arm at one end and having its other end supported to slide along a line passing through the axis of the arm and indicator, a graduated scale carried by the link, an indicator head coiiperating with and movable along said scale, a second indicator carried by said indicator head, a second graduated scale cooperating with said second indicator and arranged to be shiftable in a plane parallel with the plane of angle indication of the angle indicator, a support for said second scale carried by the arm and movable lengthwise thereof, and a third graduated scale affording longitudinal readings for variation of position of the second scale lengthwise of the arm.

9. A means for mechanically indicating the value of 5 sin. 2 0 and cos. 24)

in a stadia diagram comprising two members by varying the inclination of the transit telescope to define angles twice the angle of inclination of such telescope, a scalecarried by one of said members and adjustable to correspond to any stadia rod reading R as indicated by the transit telescope, and'two cooperating scales carried by the other member and indicating for any given angle '0 of inclination of the transit telescope and adjustment of the firstscale, the product i sin. 21) 6 and cos. 20,

respectively.

of its movement, an indicator. movably mounted upon the first mentioned scale and carrying an indicator cooperating with the second mentioned scale to give readings corresponding to the variable angle between the first and second arms due to the movement of the first arm, and a graduated scale for indicating the longitudinal position of the second mentioned scale relative to the first mentioned arm. 11. A stadia attachment for angle in'dicators,,comprising an arm movable 'proportionateiy 'with the angle-indicating member, asecond arm connected to the first arm for proportional movement relative thereto, a graduated scale carried by the second arm and partaking of its movement, a graduated scale carried by the first arm and partaking of its movement, an indicator movably mounted upon the first mentioned scale and carrying an indicator cooperating with the second mentioned scale to give readings corresponding to the variable angle between the first and second arms due to the movement of the first arm, and a raduated scale for indicating the longitudlnal position of the second mentioned scale relative to the first mentioned arm, the primary graduations of the first mentioned scale being one-half those of the other two scales.

12. A stadia attachment for angle indicators comprising an arm connected to and partaking ofthe angular movement of the angle indicator, a second arm connected to the first arm so as to be moved thereby to produce a supplemental angle therewith equal to double the angle of displacement of the first arm from normal position, a graduated scale carried by said second arm longitudinally thereof, a second graduated scale carried by the first arm transversely thereof, an

and cooperating therewith, a second inditioned scale, and means for indicating the position of the second mentioned scale relaxequal to double the angle of displacement of angle produce equal to double the angle of displacement of partaking of indicator carried by the first mentioned'scale pivotally connected to tive to the length of the first mentioned arm the primary graduations of the first mentioned scale being one-half those of the other two scales. 13. A stadia attachment for angle indicators comprising an arm connected to and partaking of the angular movement of the, angle indicator, a second arm connected to the first arm so as to be moved thereby to produce a supplemental angle therewith the first arm from normal positlon, a graduated scale carried by said second arm longi-. tudinally thereof, a second graduated scalecarried by the first arm transversely thereof, i

an indicator carried by the first mentioned scale and cooperating therewith, a second indicator carried by the first mentioned indicator to cooperate with the second mentioned scale, and means for indicating the position of the second mentioned scale relative to the length of the first mentioned arm.

14. A stadia attachment for angle indicators comprising an arm connected to and partaking of the angular movement oi the indicator, a second arm connected to the firstarm so as to be moved thereby to a supplemental angle therewith the first arm from normal posit1on,a graduated scale carried by said second arm longitudinally thereof, a second graduated scale carried by the first arm transversely thereof, an indicator carried by the first mentioned scale and cooperating therewith, and a second indicator carried by the first mentioned indicator to cooperate with the second mentioned scale, the primary graduations of the first mentioned scale being one-half those of the other scale.

15. A stadia attachment for angle indi cators comprising an arm connected to and the angular movement of the angle indicator, a second arm connected to the first arm so as to be moved thereby to produce a supplemental angle therewith equal to double the angle of displacement of the first arm from normal position, a graduated scale carried, by said second arm longitudinally there0f," a second graduated scale carried by the first arm transversely thereof, an indicator carried by the first mentioned scale and cooperating therewith, and a second indicator carried by the first mentioned indicator to cooperate with the second mentioned scale.

16. A stadia attachment for angle indicators comprising an arm for attachment .to and to swing with the angle indicator, a link said arm at one end and having its other end supported to slide along a line passing through the axis of the arm and indicator, said link having a length equal to the length of the arm between its axis and its pivotal connection with the link,

a graduated scale carried by and extending longitudinally of the link, an indicator head cooperating with and movable along said scale, a second indicator carried by said indicator head and pivoted thereon on an axis parallel with the axis of the arm,-a second graduated scale cooperating with said secondindicator'and extending transversely to said arm and said axes, said second graduated scale beingcarried by said arm and shiftable' ,lengthwi'se thereof, and a third graduated scale for-indicating the position of the second scale lengthwise of the arm.

17. A stadia attachment for angle indicators comprising an arm for attachment to and to'swing with the angle indicator, a link pivot'allyconnected to said arm at one end and having its other end supported to slide along a line passing through the axis of the arm and indicator, said link having a length equal to the length of'the arm between its axis and its pivotal connection with the link, a graduated scale carried by and extending longitudinally of the link, an indicator head cooperating with and movable along, said scale, a secondv indicator carried by said in dicator head and pivoted thereon on an axis parallel with the axisof the arm, a second graduated scale cooperating with said second indicator and extending transversely to said arm and said axes, said second graduated scale being carried by said arm and shiftable lengthwise thereof, and a third graduated scale for indicating the position of the second scale lengthwise of the arm, the primary divisions of the first scale being pivotally' connected to said ar one-half the size of'the corresponding divisions of the second and third scales.

18. A stadia attachment for .angle indi cators comprising an arm for attachment to and to swing with the angle indicator, a link at one end and having its other end supported to slide along a line passing through the axis of the arm and indicator, said link having a length equal to the length of the arm between its axis and its pivotal connection with the link, a graduated. scale carried by and extending longitudinally of the link, an indicator head cooperating with and movable along said scale, a second indicator carried by said indlcato-r head and pivoted thereon on an ax1s parallel with the axis of the arm, a second this 29th day of Decemben A. D. one thousand nine hundred and eleven. 1

ROBERT L. MCCORMICK. [L.s.] Witnesses:

ARTHUR M. Hoon, FRANK A. FAHLE. 

